stdio-common/tst-printf-round.c

   1 /* Test for correct rounding of printf floating-point output.
   2    Copyright (C) 2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <fenv.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22
  23 struct dec_test {
  24   double d;
  25   const char *fmt;
  26   const char *rd, *rn, *rz, *ru;
  27 };
  28
  29 static const struct dec_test dec_tests[] = {
  30   { 1.5, "%.0f", "1", "2", "1", "2" },
  31   { -1.5, "%.0f", "-2", "-2", "-1", "-1" },
  32   { 2.5, "%.0f", "2", "2", "2", "3" },
  33   { -2.5, "%.0f", "-3", "-2", "-2", "-2" },
  34   { 1.4999, "%.0f", "1", "1", "1", "2" },
  35   { -1.4999, "%.0f", "-2", "-1", "-1", "-1" },
  36   { 1.5001, "%.0f", "1", "2", "1", "2" },
  37   { -1.5001, "%.0f", "-2", "-2", "-1", "-1" },
  38   { 2.4999, "%.0f", "2", "2", "2", "3" },
  39   { -2.4999, "%.0f", "-3", "-2", "-2", "-2" },
  40   { 2.5001, "%.0f", "2", "3", "2", "3" },
  41   { -2.5001, "%.0f", "-3", "-3", "-2", "-2" },
  42   { 1.0 / 3.0, "%f", "0.333333", "0.333333", "0.333333", "0.333334" },
  43   { -1.0 / 3.0, "%f", "-0.333334", "-0.333333", "-0.333333", "-0.333333" },
  44   { 0.2500001, "%.2e", "2.50e-01", "2.50e-01", "2.50e-01", "2.51e-01" },
  45   { -0.2500001, "%.2e", "-2.51e-01", "-2.50e-01", "-2.50e-01", "-2.50e-01" },
  46   { 1000001.0, "%.1e", "1.0e+06", "1.0e+06", "1.0e+06", "1.1e+06" },
  47   { -1000001.0, "%.1e", "-1.1e+06", "-1.0e+06", "-1.0e+06", "-1.0e+06" },
  48 };
  49
  50 static int
  51 test_dec_in_one_mode (double d, const char *fmt, const char *expected,
  52                       const char *mode_name)
  53 {
  54   char buf[100];
  55   int ret = snprintf (buf, sizeof buf, fmt, d);
  56   if (ret <= 0 || ret >= (int) sizeof buf)
  57     {
  58       printf ("snprintf for %a returned %d\n", d, ret);
  59       return 1;
  60     }
  61   if (strcmp (buf, expected) == 0)
  62     return 0;
  63   else
  64     {
  65       printf ("snprintf (\"%s\", %a) returned \"%s\" not \"%s\" (%s)\n",
  66               fmt, d, buf, expected, mode_name);
  67       return 1;
  68     }
  69 }
  70
  71 static int
  72 do_test (void)
  73 {
  74   int save_round_mode = fegetround ();
  75   int result = 0;
  76
  77   for (size_t i = 0; i < sizeof (dec_tests) / sizeof (dec_tests[0]); i++)
  78     {
  79       result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
  80                                       dec_tests[i].rn, "default rounding mode");
  81 #ifdef FE_DOWNWARD
  82       if (!fesetround (FE_DOWNWARD))
  83         {
  84           result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
  85                                           dec_tests[i].rd, "FE_DOWNWARD");
  86           fesetround (save_round_mode);
  87         }
  88 #endif
  89 #ifdef FE_TOWARDZERO
  90       if (!fesetround (FE_TOWARDZERO))
  91         {
  92           result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
  93                                           dec_tests[i].rz, "FE_TOWARDZERO");
  94           fesetround (save_round_mode);
  95         }
  96 #endif
  97 #ifdef FE_UPWARD
  98       if (!fesetround (FE_UPWARD))
  99         {
 100           result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
 101                                           dec_tests[i].ru, "FE_UPWARD");
 102           fesetround (save_round_mode);
 103         }
 104 #endif
 105     }
 106   return result;
 107 }
 108
 109 #define TEST_FUNCTION do_test ()
 110 #include "../test-skeleton.c"